China Petrochemical Corp., Asia’s biggest refiner, agreed to invest an estimated $1 billion to increase its stake in an Australian liquefied natural gas project led by ConocoPhillips and Origin Energy Ltd.

Exxon Mobil Corp. increased the cost estimate for its liquefied natural gas project in Papua New Guinea by about 5 percent to $15.7 billion because of a stronger Australian dollar, according to partner Santos Ltd.